GB765642A - Improvements in or relating to silicone-alkyd resins - Google Patents

Abstract

A silicone-alkyd resin consists essentially of the reaction product of (1) 5 to 60 per cent (by weight) of an organosilicon compound of the general formula RnSiXmO4-n-m/2, wherein each R is a monovalent hydrocarbon or halogenated hydrocarbon radical, each X is a halogen atom, alkoxy or hydroxy radical, n has an average value of 1 to 2 and m has an average value of 0.05 to 3; (2) 10 to 35 per cent of alcohol composed of 20 to 100 per cent by weight, calculated on the total alcohol content, of trimethylolethane, 0 to 50 per cent of a dihydric alcohol and 0 to 30 per cent of another trihydric alcohol; and (3) 20 to 60 per cent of a dicarboxylic acid, anhydride or lower alkyl ester (i.e. containing less than 9 carbon atoms) thereof. The preferred method of making the resins comprises the single stage reaction of (1) 5 to 60 per cent of the organosilicon compound, (2) 10 to 35 per cent of alcohol composed of 50 to 100 per cent of trimethylolethane and 0 to 50 per cent of a dihydric alcohol, and (3) 20 to 60 per cent of a lower alkyl ester of a dicarboxylic acid, at 100 DEG to 250 DEG C. until the desired viscosity is obtained. The reaction may be effected in the presence of a catalyst such as magnesium acetate or perfluoroglutaric acid. Reactants specified are: (1) dimethyldichloro-, dibutyldi-isopropoxy-, phenylmethyldichloro, divinyldibutoxy-, tolyltriethoxy, cyclohexyl-trimethoxy-, phenylmethyldibromo-, (trifluoromethylphenyl) methyldichloro-, chlorophenyltriethoxy-, bromoxenyltrichloro-, stearylmethyldiethoxy and allylstearyloxydimethoxy-silanes, mixtures and hydrolysates thereof, diphenyl-, phenylmethyl-, dimethyl-, chlorophenylmethyl- and octadecylmethyl-silanediols; (2) ethylene glycol, neopentylglycol and glycerine; (3) malonic, adipic, maleic, dimethylmaleic, cyclohexyldicarboxylic, phthalic, terephthalic, isophthalic, naphthalic, stilbene dicarboxylic, diphenic, tolane dicarboxylic and dibenzyl dicarboxylic acids, their anhydrides and alkyl esters containing less than 9 carbon atoms. In a modification up to 50 per cent of (1) may be replaced by a drying oil and/or drying oil acid, e.g. linseed, sardine, soyabean, dehydrated castor, tung, oiticica, perilla, chinawood, hemp seed, poppy seed, safflower, sunflower or walnut oil or acid derived therefrom. The resins may be dissolved in solvents such as acetonyl alcohol, naphtha, isophorone or cresylic acid or solvent mixtures such as diacetone alcohol and butyrolactone; petroleum hydrocarbons, isophorone and methylamylacetate; acetonyl acetone and diacetone alcohol; and C6H5.OCH2.CH2.OOC.CH3 and diacetone alcohol, and used for coating metal surfaces, particularly fine wire. Examples are given. Specification 663,599 is referred to.